CO2 capture by CaCO3-MgO and CeO2-MgO sorbents promoted by ternary alkali metal salts in a fixed bed reactor

• Published in: Chemical engineering science 2024-05, Vol.289, p.119856, Article 119856
• Main Authors: Teixeira, Paula, Correia, Patricia, Pinheiro, Carla I.C.
• Format: Article
• Language: English
• Subjects: Alkali metal salts; CO2 Capture; Fixed bed reactor; MgO sorbents; Sol-gel synthesis; Supported sorbents
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2024.119856

[Display omitted] •Performance of CaCO3- AMS-MgO and CeO2- AMS-MgO sorbents in a fixed bed reactor.•Effect of the CaCO3 and CeO2 supports on the MgO crystallite size stability.•Impact of the CaCO3 and CeO2 on the AMS dispersion on the AMS-MgO sorbents.•Influence of the CO2 partial pressure on the CO2 uptake by AMS-MgO sorbents. MgO-based sorbents present a high theoretical CO2 carrying capacity which make them promising materials for CO2 capture at intermediate temperatures (200–400 °C). In this work, the MgO, CaCO3-MgO and CeO2-MgO sorbents were successfully synthesized by sol–gel technique. To enhance the CO2 capture performance a eutectic ternary alkali metal salt mixture consisting of 15 % of NaNO3/KNO3/LiNO3 (18/30/52) was added to the sorbents. The sorbents were tested in a fixed bed reactor unit along ten carbonation-calcination cycles, at 280 °C (25 % or 100 % of CO2) and 400 °C (100 % air), respectively. To identify textural, mineralogical, and morphological properties, the fresh and spent sorbents were characterized by N2 adsorption, XRD and SEM techniques. The results show that the addition of Ca or Ce precursors enhance the stability of sorbents surface area along the carbonation-calcination cycles and improves the AMS dispersion, reducing their agglomeration and contributing to the enhancement of the MgO-based sorbents’ CO2 carrying capacity.